The present invention relates to type font optical character recognition systems, and more particularly the invention relates to an improved type font oriented system so designed that a character information read by an optical scanner is compared by a pattern matching technique with each of a separately prepared set of standard character information to recognize the character read.
With printed character recognition systems heretofore known in the art, in order to eliminate any spots, voids and concavity and convexity variations in the stroke edges which are peculiar to printed characters, it has been essential to provide a preprocessing device adapted to perform the function of eliminating spots, filling in voids, smoothing out the stroke edges, etc., and this has imposed a considerable burden on the cost and the recognition rate of the systems.
As a simple read-in or input character recognition technique for the above type of systems, an input character recognition method has been proposed which comprises storing an input character information as a binary-coded data, quantizing the data by dividing it on the two-dimensional meshes of the storage plane of the memory into a plurality of segments each including an area of the same number of meshes, counting for each of the segments the number of the meshes containing the character digital data to obtain an input information in the form of a collection of a series of segment information, and recognizing the input character by performing the calculation of correlation distance or the process of pattern matching through a comparison between the corresponding segment information of the input information and each of a plurality of standard character information prepared preliminarily in the same information form as the input information, and there has existed a need for the realization of a specific system for performing the method. In this case, the number of the prepared standard character information for the pattern matching purposes is equal to the number of different characters to be recognized and the number is generally large. Thus, from the system cost point of view it is recommended to store them in an ROM (read-only memory). In consideration of the large quantity of the standard character information used, the efficient utilization of the memory capacity of the ROM to the fullest extent in turn results in a decrease in the memory capacity, and the simplification of the addressing method of the ROM is important in increasing the rate of character recognition in the systems.